use strict;
use warnings;

my $file = 'test.txt';
my $recipient = 'joe@example.com';
my ($armor) = (0);	  # 1 to generate ascii, 0 to work with binary

system('gpg',
       $armor ? qw(--armor) : (),
       '--recipient' => $recipient,
       '--encrypt'   => $file) and die "Exit code: $?";

system('gpg',
       '--output'  => "${file}_decrypted",
       '--decrypt' => $file . ($armor ? ".asc" : ".gpg"))
    and die "Exit code: $?";

system('gpg',
       $armor ? qw(--armor) : (),
       "--output"      => "${file}.sig",
       '--detach-sign' => $file) and die "Exit code: $?";